After hydrocarbons have been removed from the ground, the fluid stream (such as crude oil or natural gas) is transported from place to place via pipelines. It is desirable to know with accuracy the amount of fluid flowing in the stream, and particular accuracy is demanded when the fluid is changing hands, or “custody transfer.” Custody transfer can occur at a fluid fiscal transfer measurement station or skid, which may include key transfer components such as a measurement device or flow meter, a proving device, associated pipes and valves, and electrical controls. Measurement of the fluid stream flowing through the overall delivery pipeline system starts with the flow meter, which may include a turbine meter, a positive displacement meter, an ultrasonic meter, a coriolis meter or a vortex meter.
The fluid stream typically undergoes changes of pressure, temperature and flow rate. These changes are represented as changes in the flow characteristics, and affect accurate measurement of the product being delivered. Changing flow characteristics of the fluid stream are normally verified by the operator via the effects of the changes on the measurement device. This verification is conducted by proving the meter with a proving device, or prover in the case of liquid hydrocarbons. A calibrated prover, adjacent the measurement device on the skid and in fluid communication with the measurement device, is sampled and the sampled volumes are compared to the throughput volumes of the measurement device. If there are statistically important differences between the compared volumes, the throughput volume of the measurement device is adjusted to reflect the actual flowing volume as identified by the prover.
However, aside from the changes just described sensed by instrumentation, flow changes can manifest in other ways as well. Thus, the principles of the present disclosure are directed to overcoming one or more of the limitations of the existing processes for ensuring accuracy and reliability of the measurement station and custody transfer, and identifying maintenance issues.